Sparkplugs and Sears Mower

robertz6November 12, 2011

Has anyone seen a good short article on sparkplugs? My five year old Sears with B&S 6.75 hp motor requires a Champion RJ19HX plug, according to the manual. Sears does not carry this plug, so I ended up with a RJ19LX. The mower seemed to run hot, so I am unsure if the plug was the problem or something else was.

Sears Craftsman Model # 917.376572

Serial # 080305M 056003

Number off B&S engine 125K02-0500 E1 05072658

On a different note, can one generally replace the shaft if it gets bent, on a medium price mower like Sears, or does one simply pitch it like a real cheapy?

Changing spark plugs IMO usually waste of money. 99 times out of 100 all it needs is cleaned and gap checked. plugged back in and cranked or pull the rope and see if it got pretty blue spark. IF so it's good reguardless how old it is. I had spark plug in for 15 years all I do is clean it check gap.

As far as the bent crank shaft ususally it's cheaper just to get another mower unless you have one laying around to replace it or the cost of the crank maybe more than the time, cost and effort is worth IMO.

1. What indicates the mower is running hotter? Have you adjusted the carb leaner possibly? Have you pull the starter cover off to verify the head's cooling fins are not blocked with fine grass from mulching? If you hit something to bend Etc you might have damaged the flywheel key (thrown the timing off to cause it to run hotter). Have you checked the key?

2. Are you positive the crank is bent vs the blade? I think some shops will have jigs to straighten shafts w/o removing then. If it's not a slight bend or reasonable in cost with a satisfaction "Clause" I w/n attempt it. Be Safe In Whatever You Do!! loger

I have replaced a few 1970 - 1990 and it's not a hard job on small Briggs (Hor & Ver shafts). The challenge was to assemble the pre cleaned disassembled engines in one hour and start them. The Hor shaft was the best choice of engines due to it starting w/o a blade. The heavier flywheel was enough centrifugal force vs a kick-back. A Yearly Task, in a Small Engine Workshop. loger